1. Field of the Invention
The present invention relates to heat-activated adhesive sheets.
2. Description of the Related Art
Adhesive sheets typically using pressure-sensitive adhesives have been widely used for fixing electronic components and peripheral devices thereof in so-called “cellular phones”, etc., because they have uniform adhesive layers. It is difficult, however, to determine the position of adherends upon adhesion using these adhesive sheets and to reaffix the adhesive sheets, because the pressure-sensitive adhesives should have high tack for reliably bonding adherends. In addition, the adhesive sheets may not sufficiently reliably bond adherends in some portions to be bonded.
As a possible solution to this, Japanese Unexamined Patent Application Publication (JP-A) No. H05-179218 discloses an adhesive sheet using a heat-activated adhesive. It is difficult, however, to allow this adhesive sheet to have a small thickness, because the adhesive sheet includes a layer of a heat-activated adhesive arranged on a base material (backing) such as a nonwoven fabric. Recently, as electronic devices become more and more down-sized and thinned, demands have been made to provide thin heat-activated adhesive sheets.